http://arxiv.org/abs/1504.02285
The recent measurements of temperature and polarization of Cosmic Microwave Background (CMB) have improved our understanding of the Universe and have showed a remarkable agreement with the $\Lambda$CDM cosmological model. However, scale dependent features like power suppression in the angular power spectrum and hemispherical asymmetry in the temperature field of CMB at large angular scales, hinting at possible departure from the $\Lambda$CDM model persist in the CMB data. In this paper we present a physical mechanism linked to possible initial inhomogeneities in the inflationary scalar field that could explain both the observed phenomena. Initial inhomogeneities lead to non-zero values of anisotropic inflationary parameters, which at leading order cause different amounts of hemispherical asymmetry in the scalar and tensor perturbations. The second order effect of anisotropic inflationary parameters naturally lead to a suppression (enhancement) of power at low multipole $l$ for scalar (tensor) perturbations. This model also predicts several characteristic signatures in the temperature and polarization spectra that are accessible to future CMB missions.
S. Mukherjee and T. Souradeep
Fri, 10 Apr 15
30/68
Comments: 8 pages, 2 figures
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